/* 
 * HaoRan ImageFilter Classes v0.1
 * Copyright (C) 2012 Zhenjun Dai
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation.
 */

package com.xt.xtblesdk6.ImageFilter;
/**
 * Vignette�����Ч
 * @author daizhj
 *
 */
public class VignetteFilter  implements IImageFilter{
	
	/// <summary>
    /// Should be in the range [0, 1].
    /// </summary>
    public float Size = 0.5f;

    public VignetteFilter()
    {
       Size = 0.5f;
    }

    
    //@Override
    public Image process(Image imageIn) {
        int r, g, b, a;
        int ratio = imageIn.getWidth() >  imageIn.getHeight() ?  imageIn.getHeight() * 32768 / imageIn.getWidth() : imageIn.getWidth() * 32768 /  imageIn.getHeight();

        // Calculate center, min and max
        int cx = imageIn.getWidth() >> 1;
        int cy = imageIn.getHeight() >> 1;
        int max = cx * cx + cy * cy;
        int min = (int)(max * (1 - Size));
        int diff = max - min;

        for (int x = 0; x < imageIn.getWidth(); x++) {
            for (int y = 0; y < imageIn.getHeight(); y++) {
            	 r = imageIn.getRComponent(x, y);
                 g = imageIn.getGComponent(x, y);
                 b = imageIn.getBComponent(x, y);

                 // Calculate distance to center and adapt aspect ratio
                 int dx = cx - x;
                 int dy = cy - y;
                 if (imageIn.getWidth() > imageIn.getHeight()){
                    dx = (dx * ratio) >> 15;
                 }
                 else{
                    dy = (dy * ratio) >> 15;
                 }
                 int distSq = dx * dx + dy * dy;

                 if (distSq > min){
                    // Calculate vignette
                    int v = ((max - distSq) << 8) / diff;
                    v *= v;

                    // Apply vignette
                    int ri = (r * v) >> 16;
                    int gi = (g * v) >> 16;
                    int bi = (b * v) >> 16;

                    // Check bounds
                    r = (byte)(ri > 255 ? 255 : (ri < 0 ? 0 : ri));
                    g = (byte)(gi > 255 ? 255 : (gi < 0 ? 0 : gi));
                    b = (byte)(bi > 255 ? 255 : (bi < 0 ? 0 : bi));
                 }
         
                 imageIn.setPixelColor(x,y,r,g,b);
             }
        } 
        return imageIn;
    }

}
